authority
1.说“主管人员”或“当局者”，习惯用复数形式authorities，前面有the，如the authorities和the local authorities。
2.说“某科权威”，authority后面接on，如He used to be considered an authority on Chinese history和Harold Williams is a well-known authority on (Jonathan) Swift。
3.a well-known Swift authority=a well-known authority on Swift
